KR20230004878A - Paired dynamic parallel plate capacitively coupled plasmas - Google Patents

Abstract

Processing chambers having a plurality of processing stations and individual wafer support surfaces are described. The processing stations and wafer support surfaces are arranged such that there are equal numbers of processing stations and heaters. An RF generator is coupled to the first electrode of the first station and the second electrode of the second station. A bottom RF path is formed by a connection between the first support surface and the second support surface.

Description

Paired dynamic parallel plate capacitively coupled plasmas

Embodiments of the present disclosure generally relate to apparatus for processing semiconductor wafers. More specifically, embodiments of the present disclosure relate to processing chambers having a parallel plate capacitively coupled plasma and methods of generating the plasmas.

Atomic layer deposition (ALD) and plasma enhanced ALD (PEALD) are deposition techniques that provide control of film thickness and conformability in high aspect ratio structures. As device dimensions continue to decrease in the semiconductor industry, interest and applications using ALD/PEALD are increasing. In some cases, only PEALD can meet the specifications for desired film thickness and conformability.

Semiconductor device formation is typically performed on substrate processing platforms that include multiple chambers. In some cases, the purpose of a multi-chamber processing platform or cluster tool is to sequentially perform two or more processes on a substrate in a controlled environment. However, in other cases, a multi-chamber processing platform may perform only a single processing step on substrates; The additional chambers are intended to maximize the rate at which substrates are processed by the platform. In the latter case, the process performed on the substrates is typically a batch process, wherein a relatively large number, for example 25 or 50 substrates, are processed simultaneously in a given chamber. Batch processing is particularly beneficial for processes that are too time consuming to be performed on individual substrates in an economically viable manner, such as atomic layer deposition (ALD) processes and some chemical vapor deposition (CVD) processes.

Capacitively coupled plasma (CCP) is a well-proven method for generating a uniform plasma and is ideal for many plasma processing applications for semiconductor manufacturing. Conventional arrangements require an electrical connection for the ground path to be disconnected in-situ, when one of the electrodes of the CCP, on which the silicon wafer is placed, needs to be physically moved just before and after processing or during processing. , which makes implementation almost impossible.

Therefore, there is a need in the art for an apparatus for providing uniform plasma to parallel plate capacitively coupled plasmas for batch processing.

One or more embodiments of the present disclosure relate to processing chambers that include at least two plasma stations and a wafer pedestal having a plurality of support surfaces for supporting individual wafers for processing. An RF generator is connected to the first electrode of the first plasma processing station and the second electrode of the second plasma processing station to form an uppermost RF path. There is a connection between at least two support surfaces of the wafer pedestal to form a bottom RF path.

One or more embodiments of the present disclosure relate to processing chambers comprising: a plurality of processing stations arranged around an interior of the processing chamber, the plurality of processing stations including at least two plasma stations; a wafer pedestal having a plurality of heaters for supporting individual wafers for processing, the number of heaters being equal to the number of processing stations; an RF generator connected to the first electrode of the first plasma processing station and the second electrode of the second plasma processing station to form an uppermost RF path; and a connection between the first and second heaters of the wafer pedestal to form a bottom RF path.

Additional embodiments of the present disclosure relate to methods of processing a plurality of substrates. An RF generator coupled to the first electrode of the first plasma processing station and the second electrode of the second plasma processing station to form an uppermost RF path is powered. The first plasma processing station includes a first support surface and the second plasma processing station includes a second support surface. A connection exists between the first and second support surfaces of the wafer pedestal to form a bottom RF path.

In order that the above-mentioned features of the present disclosure may be understood in detail, a more specific description of the present disclosure briefly summarized above may be made with reference to embodiments, some of which are illustrated in the accompanying drawings. However, it is to be understood that the accompanying drawings illustrate only typical embodiments of the present disclosure and are therefore not to be regarded as limiting the scope of the present disclosure, as the present disclosure may admit other equally effective embodiments. It should be noted.
1 illustrates a cross-sectional view of a batch processing chamber in accordance with one or more embodiments of the present disclosure;
2 shows a partial perspective view of a batch processing chamber in accordance with one or more embodiments of the present disclosure;
3 shows a schematic diagram of a batch processing chamber in accordance with one or more embodiments of the present disclosure;
4 shows a schematic diagram of a portion of a wedge-shaped gas distribution assembly for use in a batch processing chamber in accordance with one or more embodiments of the present disclosure;
5 shows a schematic diagram of a batch processing chamber in accordance with one or more embodiments of the present disclosure;
6 illustrates a gas distribution assembly having openings for gas injector inserts according to one or more embodiments of the present disclosure;
7 shows a schematic diagram of a processing chamber in accordance with one or more embodiments of the present disclosure;
8 depicts a schematic diagram of a processing chamber in accordance with one or more embodiments of the present disclosure;
9 shows a schematic diagram of a processing chamber in accordance with one or more embodiments of the present disclosure;
10 shows a schematic diagram of a processing chamber in accordance with one or more embodiments of the present disclosure;
11 shows a schematic diagram of a processing chamber in accordance with one or more embodiments of the present disclosure;
12 shows a schematic diagram of a processing chamber in accordance with one or more embodiments of the present disclosure;
13 shows a schematic diagram of a processing chamber in accordance with one or more embodiments of the present disclosure.

Before describing several exemplary embodiments of the present disclosure, it should be understood that the present disclosure is not limited to details of configuration or process steps recited in the following description. The disclosure is capable of other embodiments and of being practiced or of being carried out in various ways.

As used herein, “substrate”, “substrate surface”, etc., refers to any substrate or surface of a material formed on a substrate on which a process is performed. For example, the substrate surface on which the treatment may be performed may be, depending on the application, materials such as silicon, silicon oxide, modified silicon, silicon on insulator (SOI), carbon doped silicon oxides, silicon nitride, doped silicon, germanium, gallium arsenide, glass, sapphire, and any other materials such as metals, metal nitrides, metal alloys, and other conductive materials. Substrates include, without limitation, semiconductor wafers. Substrates are subjected to pretreatment processes to polish, etch, reduce, oxidize, hydroxylate (or otherwise create or graft target chemical moieties to impart chemical functionality), anneal, and/or bake the substrate surface. may be exposed. In the present disclosure, in addition to directly treating the surface of the substrate itself, any of the disclosed film processing steps may also be performed on an underlying layer formed on the substrate, as disclosed in more detail below; , the term “substrate surface” is intended to include such underlying layers as the context indicates. Thus, for example, when a film/layer or partial film/layer is deposited on a substrate surface, the exposed surface of the newly deposited film/layer becomes the substrate surface. What a given substrate surface will contain will depend not only on the particular chemistry used, but also on what materials will be deposited.

As used in this specification and the appended claims, the terms "reactive compound", "reactive gas", "reactive species", "precursor", "process gas" and the like refer to surface reactions (e.g., chemisorption, oxidation, reduction) are used interchangeably to mean a substance having species capable of reacting with a substrate surface or a substance on a substrate surface. For example, a first “reactive gas” may simply be adsorbed onto the surface of the substrate and be available for further chemical reaction with a second reactive gas.

“Atomic layer deposition” or “periodic deposition” as used herein refers to the sequential exposure of two or more reactive compounds to deposit a layer of material on a substrate surface. The substrate, or portion of the substrate, is individually exposed to two or more reactive compounds introduced into the reaction zone of the processing chamber. In a time domain ALD process, exposure to each reactive compound is separated by a time delay to allow each compound to adhere to and/or react with the substrate surface and then be purged from the processing chamber. These reactive compounds are said to be sequentially exposed to the substrate. In a spatial ALD process, different portions of the substrate surface, or material on the substrate surface, are exposed to two or more reactive compounds simultaneously such that virtually any given point on the substrate is not simultaneously exposed to more than one reactive compound. . As used in this specification and the appended claims, the term "substantially" as used in this connection means that a small portion of the substrate is simultaneously due to diffusion, as will be understood by one of ordinary skill in the relevant art. This means that exposure to multiple reactive gases is possible and that simultaneous exposure is not intended.

As used in this specification and the appended claims, the terms "pie shape" and "wedge shape" are used interchangeably to describe a body that is a sector of a circle. For example, a wedge-shaped segment may be part of a circle or disc-shaped structure, and multiple wedge-shaped segments may be connected to form a circular body. A sector may be defined as a portion of a circle bounded by the two radii of the circle and intersecting arcs. The inner edge of the pie-shaped segment can reach a point, or it can be cut to a flat edge or rounded. In some embodiments, a sector may be defined as part of a ring or toroid.

The path of the substrates may be perpendicular to the gas ports. In some embodiments, each of the gas injector assemblies includes a plurality of elongated gas ports extending in a direction substantially perpendicular to a path traversed by the substrate, and the front surface of the gas distribution assembly is substantially parallel to the platen. Do. As used herein and in the appended claims, the term "substantially perpendicular" means that the general direction of movement of the substrates is approximately perpendicular to the axis of the gas ports (eg, between about 45° and 90°). It means follow the plane. In the case of a wedge-shaped gas port, the axis of the gas port may be considered to be a line defined as the midpoint of the width of the port extending along the length of the port.

1 shows a cross-section of a processing chamber 100 that includes a gas distribution assembly 120 and a susceptor assembly 140, also referred to as injectors or injector assemblies. The gas distribution assembly 120 is any type of gas delivery device used in a processing chamber. The gas distribution assembly 120 includes a front surface 121 facing the susceptor assembly 140 . The front surface 121 may have any number or variety of openings to direct the flow of gases towards the susceptor assembly 140 . The gas distribution assembly 120 also includes a substantially round outer peripheral edge 124 in the illustrated embodiments.

The particular type of gas distribution assembly 120 used may vary depending on the particular process being used. Embodiments of the present disclosure may be used with any type of processing system in which the gap between the susceptor and gas distribution assembly is controlled. Although various types of gas distribution assemblies may be employed (eg, showerheads), embodiments of the present disclosure may be particularly useful for spatial ALD gas distribution assemblies having a plurality of substantially parallel gas channels. there is. As used in this specification and the appended claims, the term "substantially parallel" means that the elongated axes of the gas channels extend in the same general direction. There may be some deficiencies in the parallelism of the gas channels. The plurality of substantially parallel gas channels may include at least one first reactive gas A channel, at least one second reactive gas B channel, at least one purge gas P channel, and/or at least one vacuum V channel. . Gases flowing from the first reactive gas A channel(s), the second reactive gas B channel(s) and the purge gas P channel(s) are directed towards the top surface of the wafer. A portion of the gas flow travels horizontally across the surface of the wafer and out of the processing region through the purge gas P channel(s). A substrate moving from one end of the gas distribution assembly to the other will be exposed to each of the process gases, which in turn will form a layer on the substrate surface.

In some embodiments, gas distribution assembly 120 is a rigid stationary body composed of a single injector unit. In one or more embodiments, gas distribution assembly 120 is comprised of a plurality of discrete sectors (eg, injector units 122 ), as shown in FIG. 2 . Either a single-piece body or a multi-sector body may be used with the various embodiments of the present disclosure described.

A susceptor assembly 140 is positioned below the gas distribution assembly 120 . The susceptor assembly 140 includes a top surface 141 and at least one depression 142 in the top surface 141 . Susceptor assembly 140 also has a bottom surface 143 and an edge 144 . The depression 142 may be of any suitable shape and size depending on the shape and size of the substrates 60 being processed. In the embodiment shown in Figure 1, the depression 142 has a flat bottom to support the bottom of the wafer; The bottom of the depression may vary. In some embodiments, the depression has stepped areas around an outer peripheral edge of the depression, and the stepped areas are sized to support the outer peripheral edge of the wafer. The amount of outer perimeter edge of the wafer supported by the steps may vary, for example, depending on the thickness of the wafer and the presence of features already present on the backside of the wafer.

In some embodiments, as shown in FIG. 1 , the depression 142 of the top surface 141 of the susceptor assembly 140 is such that the substrate 60 supported in the depression 142 is the susceptor 140 ) is sized to have a top surface 61 that is substantially coplanar with the top surface 141 of . As used herein and in the appended claims, the term “substantially coplanar” means that the top surface of the wafer and the top surface of the susceptor assembly are coplanar to within ±0.2 mm. In some embodiments, the top surfaces are coplanar within ± 0.15 mm, ± 0.10 mm or ± 0.05 mm. The depression 142 of some embodiments supports the wafer such that the inner diameter (ID) of the wafer is positioned within a range of about 170 mm to about 185 mm from the center (axis of rotation) of the susceptor. In some embodiments, the depression 142 supports the wafer such that an outer diameter (OD) of the wafer is located in a range of about 470 mm to about 485 mm from the center (axis of rotation) of the susceptor.

The susceptor assembly 140 of FIG. 1 includes a support pillar 160 capable of raising, lowering, and rotating the susceptor assembly 140 . The susceptor assembly may include a heater, or gas lines, or electrical components in the center of the support column 160 . The support post 160 may be the primary means of moving the susceptor assembly 140 to an appropriate position by increasing or decreasing the gap between the susceptor assembly 140 and the gas distribution assembly 120 . The susceptor assembly 140 also includes a fine-tuning actuator that can make fine adjustments to the susceptor assembly 140 to create a predetermined gap 170 between the susceptor assembly 140 and the gas distribution assembly 120. s 162 may be included. In some embodiments, the gap 170 distance ranges from about 0.1 mm to about 5.0 mm, or from about 0.1 mm to about 3.0 mm, or from about 0.1 mm to about 2.0 mm, or from about 0.2 mm to about 1.8 mm, or in the range of about 0.3 mm to about 1.7 mm, or in the range of about 0.4 mm to about 1.6 mm, or in the range of about 0.5 mm to about 1.5 mm, or in the range of about 0.6 mm to about 1.4 mm, or in the range of about 0.7 mm to about 1.3 mm, or in the range of about 0.8 mm to about 1.2 mm, or in the range of about 0.9 mm to about 1.1 mm, or about 1 mm.

The processing chamber 100 shown in the figures is a carousel-like chamber in which a susceptor assembly 140 can hold a plurality of substrates 60 . As shown in FIG. 2 , the gas distribution assembly 120 may include a plurality of individual injector units 122, each injector unit 122 on the wafer as it is moved under the injector unit. film can be deposited. Two pie-shaped injector units 122 are shown positioned above the susceptor assembly 140 and on approximately opposite sides of the susceptor assembly 140 . This number of injector units 122 is shown for illustrative purposes only. It will be appreciated that more or fewer injector units 122 may be included. In some embodiments, there are a sufficient number of pie-shaped injector units 122 to form a shape that follows the shape of susceptor assembly 140 . In some embodiments, each of the individual pie-shaped injector units 122 may be independently moved, removed, and/or replaced without affecting any of the other injector units 122 . For example, one segment may be raised to allow a robot to access the area between the susceptor assembly 140 and the gas distribution assembly 120 to load/unload substrates 60 .

Processing chambers with multiple gas injectors may be used to simultaneously process multiple wafers so that the wafers experience the same process flow. For example, as shown in FIG. 3 , processing chamber 100 has four gas injector assemblies and four substrates 60 . At the beginning of processing, substrates 60 may be placed between injector assemblies 30 . Rotating 17 the susceptor assembly 140 by 45° results in each substrate 60 between the gas distribution assemblies 120, as illustrated by the dashed circle below the gas distribution assemblies 120. ) will be moved to the gas distribution assembly 120 for film deposition. An additional 45° rotation will move the substrates 60 away from the injector assemblies 30 . With spatial ALD injectors, a film is deposited on a wafer during movement of the wafer relative to the injector assembly. In some embodiments, the susceptor assembly 140 is rotated in increments that prevent the substrates 60 from stopping under the gas distribution assemblies 120 . The number of substrates 60 and gas distribution assemblies 120 may be the same or different. In some embodiments, there are the same number of wafers in process as there are gas distribution assemblies. In one or more embodiments, the number of wafers being processed is a fractional or integer multiple of the number of gas distribution assemblies. For example, if there are four gas distribution assemblies, there are 4x wafers in process, where x is an integer value greater than or equal to one.

The processing chamber 100 shown in FIG. 3 represents only one possible configuration and should not be considered limiting the scope of the present disclosure. Here, the processing chamber 100 includes a plurality of gas distribution assemblies 120 . In the illustrated embodiment, there are four gas distribution assemblies (also called injector assemblies 30) equally spaced around the processing chamber 100. The processing chamber 100 shown is octagonal; Those skilled in the art will understand that this is one possible configuration and should not be considered limiting the scope of the present disclosure. The illustrated gas distribution assemblies 120 are trapezoidal, but, as shown in FIG. 2 , may be a single circular component or may be composed of a plurality of pie-shaped segments.

The embodiment shown in FIG. 3 includes a load lock chamber 180, or an auxiliary chamber such as a buffer station. This chamber 180 is located on the side of the processing chamber 100, for example to allow substrates (also referred to as substrates 60) to be loaded/unloaded from the processing chamber 100. Connected. A wafer robot may be positioned in the chamber 180 to move the substrate onto the susceptor.

Rotation of the carousel (eg, susceptor assembly 140 ) may be continuous or discontinuous. In continuous processing, the wafers are continuously rotated so that the wafers are exposed to each of the injectors in turn. In discontinuous processing, the wafers may be moved to the injector area and stopped, then moved to the area 84 between the injectors and stopped. For example, the carousel may rotate so that the wafers move from an inter-injector region across an injector (or stop adjacent to an injector) and onto the next inter-injector region where the carousel may pause again. there is. A pause between implanters may provide time for additional processing steps (eg, exposure to plasma) between each layer deposition.

4 shows a sector or portion of a gas distribution assembly 220 that may be referred to as an injector unit 122 . Injector units 122 may be used individually or in combination with other injector units. For example, as shown in FIG. 5 , four of the injector units 122 of FIG. 4 are combined to form a single gas distribution assembly 220 . (Lines separating the four injector units are not shown for clarity.) The injector unit 122 of FIG. 4 includes a first reactive gas port 125 in addition to purge gas ports 155 and vacuum ports 145. ) and a second reactive gas port 135, the injector unit 122 does not require all of these components.

Referring to both FIGS. 4 and 5 , a gas distribution assembly 220 according to one or more embodiments may include a plurality of sectors (or injector units 122 ) where each sector is identical or different. A gas distribution assembly 220 is located within the processing chamber and includes a plurality of elongated gas ports 125 , 135 , 145 on a front surface 121 of the gas distribution assembly 220 . The plurality of elongated gas ports 125, 135, 145 and vacuum ports 155 extend from the area adjacent the inner circumferential edge 123 to the area adjacent the outer circumferential edge 124 of the gas distribution assembly 220. is extended The illustrated plurality of gas ports include a first reactive gas port 125, a second reactive gas port 135, a vacuum port 145 surrounding each of the first reactive gas ports and the second reactive gas ports, and a purge port. It includes a gas port 155.

With respect to the embodiments shown in Figures 4 or 5, when referring to the ports extending from around at least the inner perimeter region to at least around the outer perimeter region, however, the ports are more than just radially from the inner to the outer regions. can be extended to The ports may extend tangentially when vacuum port 145 surrounds reactive gas port 125 and reactive gas port 135 . In the embodiment shown in Figures 4 and 5, the wedge-shaped reactive gas ports 125, 135 are surrounded on all edges by vacuum port 145, including adjacent the inner and outer circumferential regions. .

Referring to Figure 4, as the substrate moves along path 127, a respective portion of the substrate surface is exposed to various reactive gases. To follow path 127, the substrate passes through purge gas port 155, vacuum port 145, first reactive gas port 125, vacuum port 145, purge gas port 155, vacuum port 145. , will be exposed to or “meet” the second reactive gas port 135 and the vacuum port 145. Thus, at the end of path 127 shown in FIG. 4 , the substrate has been exposed to gas streams from first reactive gas port 125 and second reactive gas port 135 to form a layer. The illustrated injector unit 122 makes a quadrant, but may be larger or smaller. The gas distribution assembly 220 shown in FIG. 5 may be considered a combination of four of the injector units 122 of FIG. 4 connected in series.

The injector unit 122 of FIG. 4 shows a gas curtain 150 separating the reactive gases. The term “gas curtain” is used to describe any combination of gas flows or vacuum that separate reactive gases from mixing. The gas curtain 150 shown in FIG. 4 is part of the vacuum port 145 next to the first reactive gas port 125, the middle purge gas port 155 and the vacuum port next to the second reactive gas port 135. (145). This combination of gas flow and vacuum can be used to prevent or minimize gas phase reactions of the first and second reactive gases.

Referring to FIG. 5 , the combination of gas flows and vacuum from the gas distribution assembly 220 forms a separation into a plurality of processing regions 250 . Processing regions are roughly defined around individual reactive gas ports 125 and 135 with a gas curtain 150 between them. The embodiment shown in FIG. 5 consists of eight separate processing regions 250 and eight separate gas curtains 150 therebetween. A processing chamber can have at least two processing regions. In some embodiments, there are at least 3, 4, 5, 6, 7, 8, 9, 10, 11 or 12 treatment regions.

During processing, a substrate may be exposed to more than one processing region 250 at any given time. However, parts exposed to different processing areas will have a gas curtain separating the two. For example, if the leading edge of the substrate enters the processing region that includes the second reactive gas port 135, the middle portion of the substrate will be below the gas curtain 150 and the trailing edge of the substrate will be at the first reactive gas port 135. It will be in the processing area that contains the gas port 125.

Factory interface 280 , which may be, for example, a load lock chamber, is shown coupled to processing chamber 100 . A substrate 60 is shown superimposed over the gas distribution assembly 220 to provide a frame of reference. A substrate 60 may often be placed on the susceptor assembly to be held near the front surface 121 of the gas distribution assembly 120 (also referred to as a gas distribution plate). A substrate 60 is loaded onto a substrate support or susceptor assembly within the processing chamber 100 via the factory interface 280 (see FIG. 3). The substrate 60 can be shown as being positioned within the processing region as it is positioned adjacent to the first reactive gas port 125 and between the two gas curtains 150a and 150b. Rotating the substrate 60 along the path 127 will move the substrate around the processing chamber 100 in a counterclockwise direction. Accordingly, the substrate 60 will be exposed from the first processing region 250a to the eighth processing region 250h, including all processing regions in between. For each cycle around the processing chamber, using the illustrated gas distribution assembly, the substrate 60 will be exposed to four ALD cycles of a first reactive gas and a second reactive gas.

Similar to that of FIG. 5, a conventional ALD sequence in a batch processor maintains chemical (A and B) flows from each of the injectors spatially separated with a pump/purge section in between. Conventional ALD sequences have start and end patterns that can lead to non-uniformities in the deposited film. The inventors have surprisingly discovered that a time-based ALD process performed in a spatial ALD batch processing chamber provides films with higher uniformity. The basic process of being exposed to gas (A), not exposed to reactive gas, exposed to gas (B), and not exposed to reactive gas is to chemically coat the surface to avoid having a start and end pattern form on the film. We will sweep the substrate under the injectors to saturate with (A and B), respectively. The inventors have surprisingly found that the time-based approach is particularly advantageous when the target film thickness is low (e.g., less than 20 ALD cycles), where the start and end patterns have a significant impact on within-wafer uniformity performance. . The inventors have also discovered that the reaction process for producing SiCN, SiCO and SiCON films, as described herein, cannot be achieved with a time domain process. The amount of time used to purge the process chamber causes material to peel off the substrate surface. Exfoliation does not occur with the described spatial ALD process because the time under the gas curtain is short.

Accordingly, embodiments of the present disclosure provide a process comprising a process chamber 100 having a plurality of process regions 250a-250h, each process region separated from an adjacent region by a gas curtain 150. It's about methods. For example, the processing chamber shown in FIG. 5 . The number of gas curtains and processing regions within the processing chamber may be any suitable number depending on the arrangement of the gas flows. The embodiment shown in FIG. 5 has eight gas curtains 150 and eight processing regions 250a-250h. The number of gas curtains is generally greater than or equal to the number of processing regions. For example, if region 250a has no reactive gas flow and serves only as a loading region, the processing chamber will have 7 processing regions and 8 gas curtains.

A plurality of substrates 60 are positioned on a substrate support, for example the susceptor assembly 140 shown in FIGS. 1 and 2 . A plurality of substrates 60 are rotated around processing areas for processing. Generally, gas curtains 150 are engaged throughout the process, including periods when no reactive gas flows into the chamber (gas flows and vacuum is activated).

The first reactive gas (A) is flowed into one or more of the process regions 250 while the inert gas is flowed into any process region 250 into which the first reactive gas (A) is not flowed. For example, when the first reactive gas flows into processing regions 250b to 250h, the inert gas will flow into processing region 250a. An inert gas may flow through the first reactive gas port 125 or the second reactive gas port 135 .

The inert gas flow within the processing regions can be constant or variable. In some embodiments, a reactive gas is co-flowed with an inert gas. An inert gas will act as a carrier and diluent. Since the amount of reactive gas is small compared to the carrier gas, co-flow can make it easier to equalize gas pressures between processing regions by reducing pressure differences between adjacent regions.

6 illustrates another embodiment of a gas distribution assembly 120 having four injector units 122 and four openings 610 . Openings 610 may be occupied by an injector insert (not shown) that will form a uniform component. In some embodiments, the gas distribution assembly 120 has a temperature controlled body. For example, the large illustrated component with four openings 610 and four injector units 122 is cooled and/or heated using fluid channels or other cooling/heating arrangements known to those skilled in the art. It can be. The illustrated openings 610 include ledges 612 sized to support the injector insert; This represents only one possible configuration and should not be considered limiting the scope of the present disclosure.

Conventional methods and apparatus require a good ground path for RF current. This precludes using a stage that is physically moving under multiple CCP electrodes. In that case, the return path on one side of the stage, on which the opposite electrode is provided and the wafer is placed, need not be part of the RF return path. This can lead to difficulties in generating a uniform plasma (potential and ion density) across the entire wafer.

Some embodiments of the present disclosure advantageously provide an apparatus having a pair of capacitively coupled plasma (CCP) sources electrically connected in series. Some embodiments advantageously provide CCPs in which the RF current on one plasma source is returned through another plasma source. Some embodiments advantageously provide apparatus and methods for minimizing or eliminating external ground paths for RF current to return, making it suitable for mechanically dynamic plasma chambers where it is difficult to fix a good ground path.

Some embodiments of the present disclosure advantageously provide apparatus and methods for pairing two CCP stages that move together and using one CCP source as a return to the other. Some embodiments provide apparatus and methods without complex arrangements of coupling and disengagement of the RF return path.

In some embodiments, two CCP sources are connected in parallel. The bottom RF paths are interconnected. RF power is applied to the uppermost side 180 degrees out of phase with each other, and drives the RF current back and forth in a push-pull manner. RF current enters one source, exits the source from the bottom, returns from the bottom to the other source, and exits the top electrode of the other source.

The supply can be driven by two RF generators operating 180° asynchronously, or by one generator that will feed the two sides through a balun (coaxial transformer, conventional transformer, etc.). Continuity of the RF current through the two sources will allow for improved simultaneous operation of the two sources. The use of a single generator can reduce the cost of a second generator and matching circuit.

In the embodiments illustrated in Figures 2 and 3, the susceptor is a single conductive body. In some embodiments, as illustrated in FIG. 7 , separate substrate supports 710 are used and configured to act like a single wafer pedestal 700 . Four separate substrate supports 710 are connected to the cross pedestal base 720 . The pedestal base 720 is coupled to a motor 730 that can provide one or more of z-axis movement or theta movement (rotation around the z-axis). The illustrated wafer pedestal 700 has four separate substrate supports 710 and a suitably shaped pedestal base 720; One of ordinary skill in the art will appreciate that any suitable number (eg, two, three, four, five, six, etc.) of substrate supports 710 having a suitably shaped pedestal base 720 can be provided. You will recognize that there may be.

Each of the substrate supports 710 may be heated/cooled independently of the other substrate supports 710 . This allows wafers on each pedestal to be individually temperature controlled according to the particular process/reaction occurring at any given location around the z-axis. For example, a processing tool may have four separate processing regions such that each wafer is moved to some or all of the processing regions on a pedestal for multiple reactions and processes.

8-13, one or more embodiments of the present disclosure relate to processing chambers 800 and methods of providing uniform plasmas. 8, a pair of fixed electrodes 820a, 820b and a pair of moving electrodes (shown as moving heaters 810a, 810b) can be used as shown in a series circuit. Although the illustrated embodiment uses moving heaters, the present disclosure is not limited to such a device. In general, the present disclosure relates to methods of generating plasma across two or more sources by connecting the ground paths and adjusting the phases so that a physical ground is not required. In the embodiment illustrated in FIGS. 6 and 7 , there may be two or four plasma injectors (showerheads), two of which may be fired simultaneously using the phasing described herein. Plasma 815a may be ignited between the electrode 820a and the heater 810a, and another plasma 815b may be ignited simultaneously between the electrode 820b and the heater 810b. Heaters 810a and 810b can then be moved such that electrode 820a and heater 810b are paired, and vice versa. The two plasmas can be re-ignited. The same generator 830 and matching set 835 are used to power both plasmas in series. Without being bound by any particular theory of operation, having two plasmas in series means that both plasmas are ignited simultaneously and the same current passes through the two pairs of electrodes, and therefore the two wafers have similar exposures. It is believed to guarantee By alternating between the electrodes, an averaging effect is ensured for the two wafers. A coaxial cable 840 connects the two heater 810a, 810b electrodes that move with the heaters so that there is no relative motion to the physical RF connections. The reduction of RF components to one generator 830 and one matching set 835 reduces cost and complexity while ensuring wafer-to-wafer matching.

In the embodiment illustrated in FIG. 8 , coaxial cable 840 is embedded within pedestal base 720 . Coaxial cable 840 connects to the heaters and can be routed in any suitable way known to those skilled in the art. The coaxial cable 840 includes an inner conductor 842 and an outer conductor 846 and an insulator 844 therebetween.

9 shows a schematic diagram of a processing chamber 900 having substrate supports 910a, 910b and electrodes 920a, 920b. An RF source 930 with a suitable matching circuit 935 is coupled to electrode 920a and electrode 920b. Substrate supports 910a, 910b (which are heaters in some embodiments) and coaxial cable 940 are circuitry such that current 950 flows in one direction from RF source 930 back to RF source 930. Form the bottom part. Arrows representing current 950 have a thin line to distinguish current 950 from image current 960. As the skilled person will recognize, the direction of the arrows will change with the oscillations of the RF current.

In the illustrated embodiment, the top RF path (connecting 920a to 920b via RF generator 930) is an open connection. The bottom RF path (connecting support 910a to support 910b) is completed with coaxial cable 940 and connection 970 to form a full path for image current 960 flow. An RF source 930 is coupled to the electrodes through a transformer coupled balun. A balun can be used to convert the generator's output into a balanced output.

10 shows another embodiment of a processing chamber 1000 . Here, coaxial line 1040 connects the floor 1002 components (supports 1010a, 1010b) and coaxial line 1041 connects electrodes 1020a, 1020b via RF generator 1030. . RF current supplied to one plasma source (electrodes 1020a, 1020b) will return through the other source. This will create an image current 1060 that can deflect RF fields inside the process region. Using the coaxial path to complete the full circle can help form a symmetrical current distribution, but the current along the walls and across the gap 1005 between the top 1001 and bottom 1002 of the processing chamber 1000 It has a flow 1050 (which can be displacement current or reactive current). The gap in some embodiments is in the range of about 0.1 mm to about 5 mm, or in the range of about 0.5 mm to about 2 mm, or about 1 mm.

11 shows another embodiment of a processing chamber 1100. Similar to FIG. 9, the embodiment illustrated in FIG. 11 has a coaxial line 1140 connecting the bottom components (substrate supports 1110a, 1110b), while an open line 1141 connects the top components. (electrodes 1120a, 1120b and RF generator 1130) are connected. Coaxial lines may also be used to connect the top components. Here, adjustment elements 1147a and 1147b are added to bring a virtual ground to the electrodes. It is believed that this will reduce the voltage between the electrodes and the surrounding metal structure 1108 and minimize the chance of initiating a discharge in those areas. Adjusting elements 1147a and 1147b reduce the voltage between the pedestal (substrate supports 1110a and 1110b) and the surrounding metal structure 1108 to reduce the parasitic plasma.

12 shows another embodiment of a processing chamber 1200 having a dielectric brake 1270. The uppermost part of the chamber is connected in a manner similar to that illustrated in FIG. 11 . The bottom portion of the chamber is different due to the inclusion of a dielectric brake 1270. The substrate support 1210a is connected to the substrate support 1210b via a coaxial line 1240 with baluns 1247a and 1247b. A dielectric spacer 1270 separates the substrate supports 1210a and 1210b and reduces the image current at the bottom portion of the chamber. Without being bound by any particular theory of operation, it is believed that providing a dielectric break will eliminate the need for a path along the walls of the chamber. This can result in the creation of a voltage difference between the surfaces of the components.

Dielectric brake 1270 may be any suitable material known to those skilled in the art. Suitable dielectric materials include, but are not limited to, quartz, ceramics and Teflon ^® (polytetrafluoroethylene).

13 shows another embodiment of a processing chamber 1300 having a non-coaxial bottom path. RF generator 1330 connects electrode 1320a with electrode 1320b. The bottom path is formed without a coaxial line connecting substrate support 1310a with substrate support 1310b. Adjustment elements 1347a and 1347b are coupled to the outer conductor providing a return path for the image current without a coaxial line.

Additional embodiments of the present disclosure relate to processing chambers having at least two plasma stations. When used in this manner, the plasma station has an electrode, showerhead or gas distribution system that can be used to generate plasma. The plasma station may be a separate area, as in the embodiment of FIGS. 7-8, or may be separate parts of batch processing chambers, such as the processing chambers illustrated in FIGS. 1-6.

Referring again to FIGS. 8-13 , the processing chamber 800 includes a wafer pedestal having a plurality of support surfaces for supporting individual wafers for processing. 8, the support surfaces are illustrated as a pair of moving electrodes (shown as moving heaters 810a, 810b).

A plasma 815a may be ignited between the first electrode 820a and the first support surface (heater 810a), and the plasma 815b may be ignited between the second electrode 820b and the second support surface (heater 810b). ) lights up simultaneously. The support surfaces (heaters 810a, 810b) can then be moved such that the first electrode 820a and the second support surface (heater 810b) are paired, and vice versa. The two plasmas can be re-ignited. The same RF generator 830 and matching set 835 are used to power both plasmas in series. The RF generator 830 is coupled to the first electrode 820a of the first plasma station and the second electrode 820b of the second plasma station to form the top RF path. Without being bound by any particular theory of operation, having two plasmas in series means that both plasmas are ignited simultaneously and the same current passes through the two pairs of electrodes, and therefore the two wafers have similar exposures. It is believed to guarantee By alternating between the electrodes, an averaging effect is ensured for the two wafers. A coaxial cable 840 connects the two heater 810a, 810b electrodes that move with the heaters so that there is no relative motion to the physical RF connections. The reduction of RF components to one generator 830 and one matching set 835 reduces cost and complexity while ensuring wafer-to-wafer matching.

In the embodiment illustrated in FIG. 8 , coaxial cable 840 is embedded within pedestal base 720 . A coaxial cable 840 may be connected to at least two support surfaces of the wafer pedestal (eg, heaters 810a and 810b) to form a bottom RF path. Connections, including but not limited to coaxial (coaxial) cables, may be routed in any suitable manner known to those skilled in the art. The coaxial cable 840 includes an inner conductor 842 and an outer conductor 846 and an insulator 844 therebetween.

Each of the embodiments illustrated in FIGS. 9-13 are applicable to a processing chamber having at least two support surfaces and at least two plasma stations. The arrangement of components in these examples is similar to that in which the movable heater is replaced with a more general support surface. The support surface may include, but is not limited to, a movable heater.

Additional embodiments of the present disclosure relate to methods of processing a plurality of substrates. The method includes supplying power to an RF generator coupled to a first electrode of a first plasma processing station and a second electrode of a second plasma processing station to form a top RF path. During powering of the electrodes, the first support surface is located in the first plasma processing station and the second support surface is located in the second plasma processing station. The first support surface and the second support surface are connected to form a bottom RF path. Support surfaces may be movable heaters or any other susceptor type component known to those skilled in the art. In some embodiments, the method includes providing a connection between the first electrode and the second electrode and/or a connection between the first and second support surfaces, as described above with respect to FIGS. 9-13 . more includes

In the foregoing specification, embodiments of the present disclosure have been described with reference to specific exemplary embodiments thereof. It will be apparent that various modifications may be made thereto without departing from the broader spirit and scope of the embodiments of the present disclosure as recited in the following claims. Accordingly, the present specification and drawings are to be regarded in an illustrative rather than a restrictive sense.

Claims (17)

As a method of processing a plurality of substrates,
supplying power to an RF generator coupled to a first electrode of a first plasma processing station and a second electrode of a second plasma processing station to form an uppermost RF path, wherein the first plasma processing station comprises a first support a surface, wherein the second plasma processing station includes a second support surface, wherein a connection between at least two support surfaces of a wafer pedestal forms a bottom RF path, wherein the first electrode, the at least two wherein the connection between the support surfaces of the dog forms a path for RF current flow. The method of claim 1 , wherein the connection between the support surfaces is within a wafer pedestal. The method of claim 1 , wherein the connection between the support surfaces comprises a coaxial connection. 4. The method of claim 3, further comprising a second bottom RF path connecting the support surfaces. 4. The method of claim 3, wherein the top RF path is formed using coaxial cable. 4. The method of claim 3, further comprising adjusting an adjustment element coupled to each of the support surfaces. 7. The method of claim 6, wherein the adjustment element comprises a balun. 7. The method of claim 6, wherein adjusting the adjusting element reduces a voltage difference between the support surfaces and a peripheral metal structure forming the processing chamber. 4. The method of claim 3, further comprising a dielectric spacer separating the support surfaces. 10. The method of claim 9, wherein the dielectric spacer comprises one or more of quartz, ceramic or polytetrafluoroethylene. 7. The method of claim 6, wherein the bottom RF path is formed without coaxial cable. As a method of processing a plurality of substrates,
supplying power to an RF generator connected to a first electrode of a first plasma processing station and a second electrode of a second plasma processing station to form an uppermost RF path; A plasma processing station is arranged around the inside of the processing chamber, the processing chamber comprising a plurality of processing stations, a wafer pedestal having a plurality of heaters for supporting individual wafers for processing - the number of the heaters being the number of the processing stations. equal to the number of stations, and a connection between the first heater and the second heater of the wafer pedestal to form a bottom RF path; wherein the connection between the first heater and the second heater surfaces and the second electrode form a path for RF current flow. 13. The method of claim 12, wherein the connection between the first heater and the second heater is within the wafer pedestal. 13. The method of claim 12, wherein the connection between the first heater and the second heater comprises a coaxial connection. 15. The method of claim 14, further comprising a second bottom RF path connecting the first heater to the second heater. 15. The method of claim 14, further comprising adjusting an adjusting element coupled to each of the first and second heaters. 15. The method of claim 14 further comprising a dielectric spacer separating the first heater from the second heater.

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